PROVIDENCE, R.I. – Brown University says an unidentified laboratory performed an inaccurate test to determine whether a female student was drugged at a fraternity party on campus.

The Providence Journal reports (http://bit.ly/1M4xT9W ) that the lab initially reported a urine sample taken from the student tested positive for GHB, a central nervous system depressant referred to as a "date rape" drug.

University administrators said in an open letter that the laboratory recanted its findings after outside medical experts challenged the results.

The university has dropped its inquiry into drugging allegations by two female students who attended a party by Phi Kappa Psi last Oct. 17. The Rhode Island chapter of Phi Kappa Psi says no members served a spiked drink to either of the young women and challenged the laboratory's test results.